[bsdubois]

Have you checked the purge control solenoid to see if it is stuck open.

The solenoid is near the top and back of the engine. It has a two wire connector and two hoses. Disconnect the hose on the right be moving the red clip up and gently pull the connector off. Squeeze the retainer and gently pull the power connector off. Start car and check for vacuum leak. There should be no vacuum flow.

There is a YouTube video showing this. I apologize in advance if you have already tried this and I overlooked it.

Evaporative purge control solenoid.

 

[bsdubois]

Any update on your 1.8L
NA engine issues? Did your fuel pressure gauge come in and does the pressure on the gauge agree with the digital value in OBDII?

I found the intake manifold leaking on the right (passenger) side near the back. The leak is to the right of the throttle body and where the crankcase breather hose attaches. I believe the is the cause of the P0171 code and rough idle. The place of the leak is a molded vertical slit that appears to be a slot for a metal bracket. I temporarily taped the crack/leak and reset the mil light/CES codes. It idles great and no more P0171 code. I am beginning to believe built in failure points are designed into GM’s products to make work for the dealers. This part lists for over $600.00 at the dealer, no KY or gasoline is included.... not even a kiss! I found the AC Delco part online for $320.00. I may get some aluminum foil hvac tape and use it as a semipermanent fix.

I would love to have the design engineer explain why the 12mm vertical slit/slot was molded into the nylon used in the intake manifold. I would also like to meet the moron who thought plastic would be a good choice for materials in direct contact with hot aluminum. Definitely not a US engine design.








Good luck in your search for the problems. I considered purchasing a Helm shop manual, however, I am uncertain how long we will keep this pos. Honda or Toyota next. Definitely no more new GM.

Thanks for your time.